Methods

Linear mixed effects models were used to examine change in HbA1c, problem areas in diabetes (PAID) survey scores, and hypoglycemia fear survey scores over time. Participants without at least 10% automode (AM) use at their first and second visits (T1 and T2) were excluded.

For HbA1c and PAID pediatric (PAID-PEDS) scores, five models were compared using Aikaike’s Information Criterion to select the best model:

  1. A random intercept model with visit number (baseline, T1, T2) as a categorical time variable (e.g., all T2 visits would be treated the same regardless of how long the duration between T1 and T2). No adjustment for the baseline value of HbA1c or baseline PAID score.
  2. A random intercept model with visit number as a categorical time variable, with adjustment for baseline.
  3. A random intercept model with visit number as a continuous time variable, without adjustment for baseline.
  4. A random intercept model with visit number as a continuous time variable, with adjustment for baseline.
  5. A random intercept and random slope model, with adjustment for baseline.

For both HbA1c and PAID-PEDS score, the random intercept model with adjustment for baseline was the best model, so the same approach was used for the HFS survey scores.

Results

Figure 1: HbA1c by Timepoint

Table 2: A1c Mixed Models

Fixed Effects
Value Std.Error DF t-value p-value
(Intercept) 1.5548537 0.2568069 123 6.054563 0.0000000
tpointM1 -0.5800186 0.1428600 123 -4.060048 0.0000867
tpointT1 -0.5213246 0.0989040 123 -5.271014 0.0000006
tpointT2 -0.3622541 0.1159793 123 -3.123438 0.0022293
baseline_a1c 0.8240051 0.0282041 99 29.215747 0.0000000
Type 3 Tests of Fixed Effects
numDF denDF F-value p-value
(Intercept) 1 123 37279.15938 0
tpoint 3 123 42.06875 0
baseline_a1c 1 99 853.55986 0

Figure 2: PAID-PEDS by Timepoint

Table 3: PAID-PEDS Mixed Models

Fixed Effects
Value Std.Error DF t-value p-value
(Intercept) 5.3623723 2.1843390 86 2.454918 0.0161061
tpointT1 4.0201890 2.1114417 67 1.904002 0.0612055
tpointT2 0.7989866 2.3904863 67 0.334236 0.7392455
baseline_cpaid 0.8590728 0.0471021 86 18.238541 0.0000000
Type 3 Tests of Fixed Effects
numDF denDF F-value p-value
(Intercept) 1 86 1482.606752 0.0000000
tpoint 2 67 2.278222 0.1103501
baseline_cpaid 1 86 332.644362 0.0000000

Figure 3: PAID-YA by Timepoint

Table 4: PAID-YA Mixed Models

Fixed Effects
Value Std.Error DF t-value p-value
(Intercept) 1.5891767 2.3282372 10 0.6825665 0.5103825
tpointT1 -3.3315930 3.4353566 5 -0.9697954 0.3766892
tpointT2 -7.2104674 3.8360872 5 -1.8796412 0.1189315
baseline_yapaid 0.9237195 0.0756019 10 12.2182026 0.0000002
Type 3 Tests of Fixed Effects
numDF denDF F-value p-value
(Intercept) 1 10 178.857270 0.0000001
tpoint 2 5 3.350461 0.1193644
baseline_yapaid 1 10 149.284475 0.0000002

Figure 4: PAID-PR by Timepoint

Table 5: PAID-PR Mixed Models

Fixed Effects
Value Std.Error DF t-value p-value
(Intercept) 1.9851159 2.0742498 88 0.9570284 0.3411748
tpointT1 0.6807232 1.4375491 72 0.4735304 0.6372675
tpointT2 0.3961030 1.7666708 72 0.2242087 0.8232299
baseline_ppaid 0.9556595 0.0420899 88 22.7052207 0.0000000
Type 3 Tests of Fixed Effects
numDF denDF F-value p-value
(Intercept) 1 88 4448.4972615 0.0000000
tpoint 2 72 0.0491446 0.9520753
baseline_ppaid 1 88 515.5270485 0.0000000

HFS-PEDS

Fixed Effects
Value Std.Error DF t-value p-value
(Intercept) 0.7588570 0.2592075 85 2.927605 0.0043822
tpointT1 -0.3306081 0.2852693 64 -1.158933 0.2507894
tpointT2 -0.6862952 0.3289391 64 -2.086390 0.0409331
baseline_cmaintain 0.8086361 0.0500024 85 16.171935 0.0000000
Type 3 Tests of Fixed Effects
numDF denDF F-value p-value
(Intercept) 1 85 785.844575 0.0000000
tpoint 2 64 1.684996 0.1935671
baseline_cmaintain 1 85 261.531493 0.0000000

Fixed Effects
Value Std.Error DF t-value p-value
(Intercept) 0.6080379 0.5223142 83 1.164123 0.2477096
tpointT1 1.0091395 0.5114857 61 1.972957 0.0530366
tpointT2 -0.6467704 0.6011793 61 -1.075836 0.2862373
baseline_chelpless 0.9320851 0.0479968 83 19.419717 0.0000000
Type 3 Tests of Fixed Effects
numDF denDF F-value p-value
(Intercept) 1 83 1439.728029 0.0000000
tpoint 2 61 2.801757 0.0685326
baseline_chelpless 1 83 377.125412 0.0000000

Fixed Effects
Value Std.Error DF t-value p-value
(Intercept) 0.4372653 0.2660681 86 1.6434341 0.1039444
tpointT1 0.1636337 0.3315250 66 0.4935788 0.6232422
tpointT2 -0.0823585 0.3708397 66 -0.2220866 0.8249323
baseline_cworry 0.8922147 0.0461964 86 19.3135318 0.0000000
Type 3 Tests of Fixed Effects
numDF denDF F-value p-value
(Intercept) 1 86 718.9995221 0.000000
tpoint 2 66 0.6672471 0.516546
baseline_cworry 1 86 373.0125102 0.000000

HFS-YA

Fixed Effects
Value Std.Error DF t-value p-value
(Intercept) 3.9462714 2.158834 16 1.827965 0.0862621
tpointT1 -7.5424232 2.797023 13 -2.696590 0.0183126
tpointT2 -4.5318317 3.195114 13 -1.418363 0.1796105
baseline_yabehavior 0.6911614 0.114006 16 6.062498 0.0000165
Type 3 Tests of Fixed Effects
numDF denDF F-value p-value
(Intercept) 1 16 85.950478 0.0000001
tpoint 2 13 1.622625 0.2349147
baseline_yabehavior 1 16 36.753884 0.0000165

Fixed Effects
Value Std.Error DF t-value p-value
(Intercept) 4.8450260 2.4190915 16 2.002829 0.0624393
tpointT1 -7.1799721 3.4722557 13 -2.067812 0.0591632
tpointT2 -4.8826332 4.0095624 13 -1.217747 0.2449621
baseline_yaworry 0.6619749 0.0945556 16 7.000907 0.0000030
Type 3 Tests of Fixed Effects
numDF denDF F-value p-value
(Intercept) 1 16 64.100689 0.0000005
tpoint 2 13 1.840381 0.1978010
baseline_yaworry 1 16 49.012701 0.0000030

Fixed Effects
Value Std.Error DF t-value p-value
(Intercept) 9.305345 4.4341964 16 2.098542 0.0520854
tpointT1 -14.579047 5.9223115 13 -2.461716 0.0285766
tpointT2 -9.336832 6.8197369 13 -1.369090 0.1941616
baseline_yatotal 0.656770 0.1047593 16 6.269323 0.0000112
Type 3 Tests of Fixed Effects
numDF denDF F-value p-value
(Intercept) 1 16 81.883556 0.0000001
tpoint 2 13 1.943715 0.1825865
baseline_yatotal 1 16 39.304412 0.0000112

HFS-PR

Fixed Effects
Value Std.Error DF t-value p-value
(Intercept) 0.9453148 0.2400182 87 3.938513 0.0001649
tpointT1 -0.8129303 0.2285603 76 -3.556743 0.0006504
tpointT2 -1.0875560 0.2755842 76 -3.946365 0.0001756
baseline_pmaintain 0.8092222 0.0396487 87 20.409807 0.0000000
Type 3 Tests of Fixed Effects
numDF denDF F-value p-value
(Intercept) 1 87 1900.35318 0.00e+00
tpoint 2 76 13.38951 1.04e-05
baseline_pmaintain 1 87 416.56022 0.00e+00

Fixed Effects
Value Std.Error DF t-value p-value
(Intercept) 4.5547249 1.1734158 88 3.881595 0.0002001
tpointT1 -0.9350061 0.9603182 77 -0.973642 0.3332831
tpointT2 -1.5676472 1.1782036 77 -1.330540 0.1872674
baseline_phelpless 0.7100953 0.0637917 88 11.131465 0.0000000
Type 3 Tests of Fixed Effects
numDF denDF F-value p-value
(Intercept) 1 88 993.577970 0.000000
tpoint 2 77 1.092661 0.340465
baseline_phelpless 1 88 123.909520 0.000000

Fixed Effects
Value Std.Error DF t-value p-value
(Intercept) 0.5113294 0.2418905 87 2.1138883 0.0373872
tpointT1 -0.5098216 0.3000966 78 -1.6988582 0.0933315
tpointT2 0.1407073 0.3617574 78 0.3889549 0.6983693
baseline_pworry 0.8568921 0.0430542 87 19.9026199 0.0000000
Type 3 Tests of Fixed Effects
numDF denDF F-value p-value
(Intercept) 1 87 515.737842 0.0000000
tpoint 2 78 4.531658 0.0137441
baseline_pworry 1 87 396.114279 0.0000000